江西省新一代中短期预报业务流程介绍

按照中国气象局以数值预报产品为基础,以MICAPS预报人机交互系统为工作平台的思路．建立了包括气候背景、预报思路、天气会商、预报制作和管理5个模块的江西省新一代中短期预报业务流程,并重点介绍了数据转换、综合图定义、参数修改、网络改造等有关的本地化工作,以及包括天气形势描述、要素预报的人机交互修改、全省实况描述的预报制作和预报产品自动或半自动生成技术。     

浅析张集矿立井地面预注浆堵水效果

介绍了张集矿立井基岩段水文地质和基岩地面预注浆的有关情况。根据井简实测资料,分析基岩裂隙的发育规律、裂隙层界面的浆波充填情况、实际浆液有效扩散半径及堵水效果。认为：立井基岩地面预注浆,不仅能成功地起到堵水的自的．从而缩短工期、降低造价、提高质量,而且还有利于井筒安全揭穿突出谋层,达到安全施工。     

Transport of moderately sorted gravel at low bed shear stresses: The role of fine sediment infiltration

A reliable estimation of sediment transport in gravel‐bed streams is important for various practical engineering and biological studies (e.g., channel stability design, bed degradation/aggradation, restoration of spawning habitat). In the present work, we report original laboratory experiments investigating the transport of gravel particles at low bed shear stresses. The laboratory tests were conducted under unsteady flow conditions inducing low bed shear stresses, with detailed monitoring of the bed topography using a laser scanner. Effects of bed surface arrangements were documented by testing loose and packed bed configurations. Effects of fine sediments were examined by testing beds with sand, artificial fine sand or cohesive silt infiltrated in the gravel matrix. Analysis of the experimental data revealed that the transport of gravel particles depends upon the bed arrangement, the bed material properties (e.g., size and shape, consolidation index, permeability) and the concentration of fine sediments within the surface layer of moving grains. This concentration is directly related to the distribution of fine particles within the gravel matrix (i.e., bottom‐up infiltration or bridging) and their transport mode (i.e., bedload or suspended load). Compared to loose beds, the mobility of gravel is reduced for packed beds and for beds clogged from the bottom up with cohesive fine sediments; in both cases, the bed shear stress for gravel entrainment increases by about 12%. On the other hand, the mobility of gravel increases significantly (bed shear stress for particle motion decreasing up to 40%) for beds clogged at the surface by non‐cohesive sand particles. Copyright © 2017 John Wiley & Sons, Ltd.     

Fault geometrical model of Dujiangyan section in Longmenshan fault zone

The focal mechanism solution on the seismic fault plane can reflect the geometric and kinematic characteristics of faults, and it is an important way to further study the fine structure of fault plane. From the focal mechanism solution of the earthquakes around the Dujiangyan fault in Longmenshan fault zone, we derived the average dip angle of Dujiangyan fault is 45.1° based on the seismic moment tensor theory. In order to refine the fault geometry structure, this paper decomposed it into multiple sub-fault planes along the length and width of the fault plane and forms a number of models A13, B13, A23 a, A23 b, A23 c, B23 a,B23 b and B23 c, then calculated the sub-fault's dip of each model. In order to clarify exactly which one of the fault models is closest to the real fault model, the fault slip was carried out for each model in turn, then compared the surface displacement of each model with GPS observations. The results show that B23 c model with high dip in shallow and small dip in deep is the best model, the lengths of each subfault of Dujiangyan fault from south to north are 33 km, 21 km and 46 km, respectively. When the depth of the fault bottom is about 11 km, the dip angles are 70.56°, 67.41° and 45.55°.When the depth of the fault bottom is about 30 km, The fault dip angles are 44.55°, 29.18° and 44.25°.     

实景三维精细建模优化方法探索与实践

对比分析目前常用的几种实景三维建模方法及适用性,剖析倾斜摄影三维建模技术在几何结构和模型纹理等方面存在的问题,提出了实景三维精细建模的优化方法和技术路线,着重阐述了高低空航摄相结合的关键技术,明显改善了模型效果,提高了建模的质量与效率,为实景三维数字城市建设提供了技术参考.     

基于EC细网格产品在乌鲁木齐机场低能见度预测中的释用

利用2015—2018年乌鲁木齐机场航空例行天气报告(METAR报)、ECMWF(European Centre for Medium-Range Weather Forecasting)细网格数值预报产品对影响能见度的主要因子进行分析,提取与低能见度相关性高的物理量作为预报因子,采用SVM方法,分别基于Poly、RBF核函数建立乌鲁木齐机场未来21 h能见度预报模型。结果表明:(1)基于预报因子区间分类的SVM模型物理意义明确,试验结果较好;以RBF为函数建立的SVM模型(SVM-RBF)预报能力更好,其训练样本预测的TS评分0.84,准确率89.20%。(2)SVM-RBF模型的检验样本中,预报准确样本的预报误差整体偏小;在漏报样本中则有能见度越低、预报误差越大的特点,模型的振荡性明显。(3)结合NCEP/NCAR再分析资料研究SVM-RBF模型对天气过程的预报表现,发现模型对于特定天气形势下引发的低能见度天气,预报误差较小且预报提前量较大。     

太行山片麻岩区坡地渗流集蓄技术

在分析国内外雨水利用历史、现状的基础上,对太行山片麻岩坡地的水文地质结构及特性进行了分析。结果发现,坡地的表层被一层双重、非均匀的复杂介质所覆盖,具体表现为“上覆土壤、下伏岩石”的“岩土二元结构体”;岩土二元结构坡地的空间变异性,特别是岩一土之间存在凹凸不平交界面的水文地质特性,为坡地侧向渗流的集蓄创造了条件,该技术创新了雨水集蓄的形式,在中国北方石质山地具有广泛的推广与应用价值。     

Provenance discrimination of fine sediments by mid-infrared spectroscopy: Calibration and application to fluvial palaeo-environmental reconstruction

Determining sediment provenance allows a better understanding of fluvial palaeo-dynamics, and identifying involved watersheds, at broad spatio-temporal scales. Conventional approaches for source identification are usually based on the physical, mineralogical, geochemical, magnetic or isotopic properties of sediments. Rapid, non-destructive and, in well-established contexts, highly accurate, mid-infrared spectroscopy is an alternative method for investigating sediment sources. The present research objectives are: (i) to use the mid-infrared spectroscopy method to discriminate the provenance of fine sediments, by applying discriminant analysis on a large set of reference samples from three different watersheds in the Upper Rhine area (associated with the Rhine, Ill and Vosges tributaries); (ii) to clarify whether the provenance spectra signatures are influenced by riverine depositional contexts (bars versus banks) and, to some extent, by grain size and/or high organic matter content; and (iii) to apply the mid-infrared spectroscopy – discriminant analysis method to a study of fluvial palaeo-dynamics and determine the provenance of palaeo-channel infillings. Three main sedimentary sources, divided into eight sub-categories, have been characterized by 196 modern reference samples from 78 collecting sites. Discriminant analysis displayed a strong separating power by classifying correctly the origin of samples without any inter-group overlap, independently from the geomorphological context (bar or bank) and associated slight changes in organic matter contents or grain size. Mid-infrared spectroscopy – discriminant analysis investigations of the palaeo-channel infill, complemented by radiocarbon dates and mineralogical data, allowed reconstructing general trends for the local morpho-sedimentary dynamics over the last ca 12 millennia.     

分形岩石裂隙中渗流扩散运动的试验研究

由于存在大量粗糙不规则裂隙,使得岩体中流体运动极为复杂。针对天然粗糙岩石裂隙渗流试验存在物理模型隐蔽性和不可重复性等难点,基于三维Weierstrass-Mandelbrot分形函数构建了粗糙节理面的裂隙通道,采用3D打印技术获得了透明精细的裂隙模型,使用微流体控制仪研究了不同试验条件下的裂隙渗流扩散运动,分析了裂隙通道流量与压力水头、裂隙宽度和分形维数之间的关系。研究结果表明：与平行板立方定律近似,在分形裂隙中,裂隙通道流量与压力水头成线性关系;单宽流量与裂隙通道的宽度成近似的三次方关系;考虑分形维数影响时,相同条件下流过裂隙通道的流量随着分形维数的增加而增加;粗糙裂隙渗流立方定律可采用与分形维数相关的幂指数函数进行修正。     

断裂带首波研究进展

断裂带首波是沿着存在物性差异界面传播的一种地震折射波,在传播过程中携带了断裂带的重要信息,对分析和研究断裂带以及附近区域的精细结构提供了一种新的分析方法。本文主要阐述断裂带首波的产生原理、波形特征、识别及分析方法等,介绍目前国际上识别及利用断裂带首波开展断裂带特征方面的研究现状,并针对地震危险区域存在物性差异的断裂带,提出可结合密集台阵观测技术,利用断裂带首波进行断裂带精细结构探测及其变化监测研究,提高潜在孕震环境及发生机理的认识水平。